Friction element



Oct. "7, 1941.l c. BocKlusu ETAL 2,258,237

'FRICTION ELEMENT original Fired Nov. 2o, 1935l @mais acuas l Patented @et 7, 194i f m i il 2,25%,237 lIFRIG'IION ELEMENT Chris Bockius, Ridgewood, and Judson A. Cook,

Haledon, N. J., assgnors to Raybestos-Manhattan, Inc., Passaic, N. J., a corporation of New Jersey Original application November 20, 1935, Serial No. 50,802. Divided and this application July 18, 1938, Serial No. 219,797

(ci. isz- 101) 6 Claims.

This application is a division of our co-pending application Serial No. 50,802, filed November20,

1935, issued September 20, 1938 as U. S. Patent This invention relates to improvements in friction elements for use as clutch facings, brake linings and the like. The novel product of this invention comprises a structure having no splices, staples or other hard projecting areas of juncture, constructed by endlessly winding fibrous yarn or f roving into an endless wound structure.

'I'he invention will be described with particular reference to its embodiment in a clutch facing, but it is to be understood that the invention embraces brake linings as well as clutch facings.

Among the objects of this invention are to provide an endless friction facing devoid of splices, vthus eliminating variations in density and insuring uniformity of the facing throughout its, entire contact area; to provide a facing having an un- Cil Yusually high resistance to centrifugal force; to v provide a facing especially adapted for use with crimped pressure plates; to'provide a structure which lends itself to economical manufacture, since there is no cutting or waste of material other than that lost in the grinding operation, which is negligible; to provide a structure in which, due to the peculiar spider-web method of winding and the manner in which the wave form strands fall over and overlap while curing, there is no danger of ply separation; to provide a struc-I ture in which the possibilityfof scoring is eliminated since it has no symmetrical pattern, and in general to provide an improved friction element for the purposes herein described.

Resistance to centrifugal force is becoming `more and more important with the growing popularity of high speed engines and clutches, which may be disengaged at thse high speeds, with the result that the side holding'power of the Dpres*- sure plate andfiywheel plate are removed. This bear upon the facing which it must resist with its own strength. Since the clutch facing of the present invention is devoid of splices, greater re- I sistance to centrifugal force is obtained and hence the friction facing of this invention is especially4 adapted for use at the present time. 4

This invention overcomes the `objection of straight wound yarn, in that the loops of each being made to obtain controlled placing of the l yarn with reference to the location of the yarn in the previous turn. Theseliave been found to be deficient in strength to retain the rivets and the strands may have a tendency t unwind or unravel, furthermore the facing may be sheared into separate concentric 'rings in line with the rivet circle or other sections of the ring which may show a weakness of adhesion circumferen-` tially.

The construction provided in our pattern prevents any possibility of the facing shearing cir cumferentially at any place, including the rivet circle.

Friction elements made in accordance with the present invention do not nullify the action ofY crimped pressure plates as do other types of facv `ings which, due to their rigidity, provide no cushioning action to take up the tolerances and ir' regularities of manufacture of the metal parts of the clutch.

From the viewpoint ofY economy of manufacture, while the friction element of the present invention has al1 the advantages of the woven type, the expense of weaving is saved. In addition, since the element has no symmetrical pattern the possibility of scoring is eliminated, asl opposed to some types of Woven structures here'- tofore proposed.' (when the woven material is coned to form a ring) which have relatively high knuckles or loops in the warp threads which follow each other successively in `one circumferential path, causing undue local abrasion or scoring.

In the drawing,

Rig. 1 is a face view of a friction facing comprising the concepts of our invention.

Fig. 2 is an edge view of the facing shown in Fig. 1. I

- Our invention involves the forming of friction y elements by winding yarn or roving on a suitable action brings a very high centrifugal force to f form. The yarn or roving may be entirely of fibre, such as asbestos or cotton or combinations of different types of fibre, the preferred yarn or roving being asbestos with sufficient cotton to give it the required strength. Another common ,type of yarn or roving used in 'making friction elements is a combination Vof metal wire, such as vbrass or copper, with a fibrous material, such as asbestos or cotton or both. Sometimes this type. of yarn is'formed by winding the fibrous yarn or roving about the wire or the wire and fibrous yarn are twisted together, and this twisted yarn may comprise more than one strand of wire or more than one strand of yarn, as for instance two `lstrands of wire and'three strands of fibrous yarn or roving twisted together. After impregnating'the yarn or roving with a suitable binder it is preferably dried and wound. The element afterbeing wound-is preferably compressed in a suitable mould to give it the desired density and shape.

Referring in detail to the drawing, I indicates afriction element which is constructed of fibrous or two or more single strands may constitute one Y unit strand, as shown best at 3 in Fig. 2.

In winding the strands, the strands are wound upon a"rotating mandrel (not shown), and are guided by means of a reciprocating guide (not shown) back and forth along the axis of the mandrel, the rate of rotation of the mandrel and the rate of reciprocation of the guide may [be so correlated as to wind the strands in wave fashion circumferentially around the mandrel, the wave preferably repeating itself a plurality of times during each revolution of the mandrel. In addi- Ition, the rate of rotation of the mandrel, the rate of reciprocation'of the guide and the size of the facing is so correlated that the waves of each layer, corresponding to each revolution of the mandrel, lock or lead the waves of an adjacent layer in such a manner that a large number of revolutions of the mandrel takes place before the wave of a predetermined layer comes into phase with the wave of a previously laid layer.

Also in winding the facing the throw of the guide is such that a friction facing of conventional thickness, after compression and cure, is

obtained, and in addition the number of layers is such as to build up a radial width equal, after compression and cure, to that of the conventional friction facing. .Of course, as in the case of the conventional friction facing, the working face of the facing is parallel to its radial width and at i right angles to the spiral planewhich` embraces the wave hereinbefore described. ;11

The strands of yarn 2 prior to winding, if desired, may be impregnated with any of the conventional binders employed in friction materials or after Winding, the facing, as a. whole, may be impregnated.

After winding the Structure I the same may be compressed to the approximate dimensions of the finished facing. The` compacted structure may then be placed-in molds (not shown) and further compressed and cured to the finished state thereby providing an endless friction element which is ideally adapted for use as a clutch facing or for like uses. Of course, after curing the facings the same are ground and baked or heat treated in the usual manner and rivet holes may be punched therein.

In impregnating the strands 2, as has been hereinbefore described, any of the well known saturants or binders used in the manufacture of friction materials can be utilized, such as, rubber, latex, oxidizable oils, resins, bitumens, colloidal mixtures, or the like. 1f desired, the rst windings of the structure I may be saturated with one saturant or a predetermined ,concentraa suitable'binder prior to winding, it is to be understood that the invention in its broader aspects includes the winding of unsaturated yarn or roving in which case the wound structure would be saturated as well as the step of saturating or A impregnating the wound structure with a suitable binder even when made from previously impregnated yarn.`

We claimas our invention: y

1. A friction facing of greater radial width than the thickness Vcomprising a bonded, compressed structure composed essentially of end# lessly wound Strands comprising asbestos Wound in superimposed layers, said layers being disposed at substantially right angles to the working face of the facing, each layer comprisingV an unwoven strand wound in wave fashion, said waves being disposed in the plane of said layers.

2. A friction facing of greater radial width than thickness comprising a bonded, compressed structure composed essentially of endlessly Wound strands comprising asbestos helically woundin superimposed layers, said layers being disposed at substantial right angles to the working face of the facing, each layer comprising an unwoven strand Woundrin wave fashion, said waves being disposed substantially in the plane ofv said layers.

3. A friction facing of greater radial width than thickness comprising a bonded, compressed structure composed essentially of endlessly Wound strands comprising asbestos wound in superimposed layers, said layers being disposed at sub-l stantially right angles to the' Working face of the facing, each layer comprising an unwoven strand wound in wave fashion, said Waves being disposed substantially in the plane of said layers and each wave repeating itself a plurality of times in each layer.

4. A friction facing of greater radial width than thickness comprising a bonded, compressed, cured structure composed essentially of endlessly wound strands comprising binder treated asbestos wound in superimposed layers, said layers being disposed at substantially right angles to the working face of the facing, each layer comprising an unwoven strand Wound in wave fashion, said wave repeating itself a plurality of times in each layer, and said Waves being disposed in the plane of said layers.

5. A friction facing of greater radial width than thickness comprising a bonded, compressed,

tion ofl a predetermined saturant and the last 'v `windings may be saturated with a different characteristics to different portions of the facing.

While we have specifically described the ini vention utilizing yarn or roving impregnated with cured structure, composed essentiallyof endlessly wound impregnated or treated ber yarn including asbestos-and Wire strands Wound in superimposed layers, said layers being disposed at substantially right angles to the working face of the facing, each layer comprising an unwoven strand wound in' wave fashion, said waves being disposed in the plane of said layers, and each wave repeating itself a plurality of times in each layer. 6. A friction facing of ,greater radial width than thickness comprising a bonded, compressed, cured structure composed essentially of endlessly wound yarn impregnated with binders andrilllers, the yarn comprising fibers including asbestos and being wound in superimposed layers, said layers being disposed at substantially right angles to the working face of the facing, each layer comprising an unwoven strand wound in wave fashion, said waves being disposed substantially in the plane of said layers, and each wave repeating itself a plurality of times in each layer.

' CHRIS BOCKIUS.

JUDSONv A.- CQOK. 

